Can body



NOV. 4, 1952 Q W HElNLE 2,616,588

CAN BODY Filed NOV. 16, 1945 .IIIJ 7....

ATTORNEYS Patented Nov. 4, 1952 CAN BODY Carl W. Heinle, East Orange, N. J., assigner to American Can Company, New York,`N. Y., a corporation of New Jersey Application November 16, 1945, Serial No. 629,10?l

1.Claim. (Cl. 22o-76) The present invention relates to` containers or cans and has particular reference to improvementsin reenforcing the side seam of acan body and more specically to improvements on the can bodies disclosed in United States Patent 2,064,537, issued December 15, 1936 to W. E. Groenke, on Can Body and in United States Patent 2,259,498, issued October 21, 1941, to R. C. Taylor, on Can Body.

The present invention contemplates the provision of a can body having a side seam capable of withstanding the high internal pressures developed in some liquids such as beer when enclosed and hermetically sealed in cans made from such bodies and when pasteurized or otherwise treated. In the manufacture of such cans it has been found necessary for best results to provide venting notches in the interfolded hooksof the side seam and to press a porti-on of these hooks into the notches to obtain proper flow of molten solder by capillary action throughout all parts of the seam to insure against the formation of islands or other unsoldered portions when the seam is soldered. In such a reenforced side seam, such as disclosed in the above mentioned Groenke and Taylor patents, portions of the hooks are bent back on themselves in a sharply bent fold.

Where the interior of the cans are pre-coated with an enamel or other coating substance which includes the tin coating, some diiculty has been experienced in the cracking of theV enamel or other coating substance at the sharp bends in the folds with the result that the base metal of the body is exposed to the corrosive action of the contents of the can. The instant invention is directed to overcoming this dinculty by the elimination of the sharp bends in the folds of the seam.

An object of the invention is the provision of a sheet metal can body capable of withstanding high internal pressures and having an improved reenforced side seam made up of a plurality of sections or Zones of different thicknesses of material constituting interlocked and embedded hooks and overlaps separated by reentrant notches and nodes formed along the side seam edges of the body while maintaining `the seam free oi any sharp folds which tend to crack any coating on the can body material to prevent exposure of the base material at the folds and to provide capillary action for solder applied to the outside of the seam to insure a fully bonded seam free of islands or other unsoldered portions.

Numerous other objects and advantages of the invention will be apparent as it is better understood-from the following description, which, taken in connection with the accompanying drawings, discloses a preferred embodiment thereof.

Referring to the drawings:

Figure 1 isA a perspective view of a can body embodying the instant invention;

Fig. 2 is a perspective view of a formed can body blank from which the body shown in Fig. 1 is made:

Fig. 3 is an enlarged longitudinal section of a portion ofthe side seam and the adjacent body Wall being taken substantially along the line 3-3 in Fig. 1 and illustrating the different zones of thickness of the blank parts in the side seam;

Fig. 4 is an enlarged fragmentary section taken substantially along the line 4--4 in Fig. 3;

Figs. 5 and 6 are enlarged fragmentary sections taken substantially along the line 6--6 in Fig. 3, Fig. 5 illustrating the position of the different zones of thickness of the blank parts in the side seam before the seam is fully bumped, and Fig. 6 illustrating the position ofthe same blank parts after the Yseam is bumped as shown in Fig. 3; and

Figs. 7 and 8 are views similar to Figs. 5 and 6 and illustrating a modified rform of the invention.

As a preferred embodiment ofy the instant invention the drawings illustrate a sheet metal can body A (Fig. l) made of tin plate or the like material and produced from a formed blank II (Fig. 2) having an outside hook I2 and an inside hook I3 respectively disposed along the opposite side seam edges of the blank. The outer hook I2 is formed with a series of longitudinally spaced reentrant or vent notches I4 which extend transversely of the hook for its full width, each of these notches constituting a vent channel extending from the outside of the body into the interlocked hooks of the seam (Figs. 5 and 6).

In producing the can body A from the formed blank II, the side seam hooks I2, I3 are interengaged in the usual manner and are bumped or pressed down fiat to interlock the hooks as shown in Fig. 4. This produces the well known lock type side seam, the notches I4 in the outer hook I2 being disposed inside the seam adjacent the inner hook I3, as shown in Fig. 5. During this bumping or pressing operation a portion of the body wall adjacent the enclosed notches I4 is pressed inwardly into the notches, as best shown in Figs. 3 and 6, to ll in the spaces and to reduce the thickness oi the seam at each notch to reeniorce the seam. This forms a plurality of depressions I6 in the seam, with the notches filled longitudinally of the seam, and only partially filled for the depth of each notch, transversely of the seam. This partial lling leaves the original curved line of bend of the inner hook unchanged.

Since this pressing of the wall of the body into the notches I4 for merely the width of the notches does not in any way compress the outer hook I2, there is no sharp bending of the hook along its line of fold. Hence there is no cracking of the tin coating or other coating substance on the body along this line of fold.

However, unless special precaution is taken in the pressing of the seam, cracking of the tin coating or other coating substance along the line of fold of the inner hook I3 will take place. According to the present invention, the depression I6 is formed only partially across the seam and. terminates immediately adjacent this lineV of fold. This prevents the fold of the inner hook from being tightly creased or broken. Hence the original line of fold or curved line of bend of the inner hook I3 is preserved as a loop or open node II (Fig. 6) at the notches I4 with the result that the coating on the base metal remains unbroken and intact for protecting the base metal against exposure and corrosion.

Where it is desired to form the side seam on the outside of the can body so as to leave the interior smooth, the modified form of the invention as shown in Figs. '7 and 8 may be used. In this modified form of the invention the wall of the body on the outside and the inner hook I3 are pressed inwardly and this action pushes the inner hook down into the notches I4. In this pressing operation depressions I8 are made in the outside of the seam at the notches I4, thereby leaving the inside surface of the seam smooth and straight.

However, these depressions are not formed entirely across the seam but are terminated just short of the line of fold of the inner hook I3. Hence this line of fold is preserved, as in the preferred form of the invention, as open loops or nodes I9 with the result that the coating on the base metal remains unbroken and intact for protecting the base metal against exposure and corrosion.

This termination of the depressions I8 just short of the line of fold of the inner hook I3 also provides a venting node 23 in the wall of the body adjacent and surrounding the node I9. This outer or surrounding node partiallyr encloses the node I9 and thereby sets off a narrow channel between the nodes which facilitates the flow of molten solder by capillary attraction throughout the parts of the seam at the vent notches, when the seam is subsequently soldered.

The interengaging of the hooks I2, I3 of the body and the pressing of them together to form the side seam as just described are done automatically during the manufacture of the can body by the usual body maker or other type of body forming machine. The side seam is then hermetically sealed by the introduction of molten solder applied from the outside of the body in the usual manner. The distribution of the solder in the inally prepared seam is graphically illustrated in Figs. 3, 4, 6 and 8, the solder being designated by the numeral 22. In these figures, which are drawn on an enlarged scale, it has been necessary to greatly exaggerate the thickness of the body wall and also the thickness of the solder. This should be kept in mind when viewing these figures. In reality there is practically metal -to metal contact in the hooked sections of the seam and the film of solder therebetween is indeed very thin.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

I claim:

A reenforced tubular metal can body capable of resisting high internal pressures and provided with a protective coating and having edge portions joined in a side seam, said side seam including portions of the side wall of said body and outer and inner reversely bent hooks emerging from said body side wall in curved lines of bend designed to prevent cracking of the protective coating on said body, said hooks being interlocked and united by a solder bond, said outer hook being cut away at spaced intervals to form open notches extending from the terminal edge of said hook entirely across said hook and around the line of bend of said hook, said notches terminating in the adjoining wall of said body to provide vent channels extending from the outside of said body into the interlocked hooks of said side seam to facilitate soldering of said seam, said inner hook being continuous and unnotched, said body side wall adjoining said inner hook having spaced portions coincident with said notches in said outer hook compressed into said notches in spaced relation to the curved line of bend of said inner hook, said curved line of bend of said inner hook eX- tending continuously and uniformly throughout substantially the length of the can body to preserve said line of bend and the continuity of the protective coating thereon, said preserved line of bend defining in said inner hook a plurality of longitudinally spaced hollow loops each communicating with one of said notches in said outer hook and through said notches communicating with the outside of the body to facilitate venting of the inner reaches of said side seam during the soldering of said seam, said compressed portions of said body side wall substantially lling said notches in a direction longitudinally of said seam and only partially lling said notches in a direction transversely of said seam to maintain said hollow loops in an open condition for seam venting purposes.

CARL W. HEINLE.

REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS Great Britain May 16, 1939 

